• We’re currently investigating an issue related to the forum theme and styling that is impacting page layout and visual formatting. The problem has been identified, and we are actively working on a resolution. There is no impact to user data or functionality, this is strictly a front-end display issue. We’ll post an update once the fix has been deployed. Thanks for your patience while we get this sorted.

Confusing RAM problem on P5A mobo

kranky

kranky

Elite Member
I'm helping a friend by putting more RAM on his motherboard. It's an old ASUS P5A (Socket 7) running an AMD K6-III/450 and has three DIMM slots. Started with a 64mb DIMM and a 128mb DIMM, third slot empty, was working fine. This mobo says it can support three PC100 DIMMs up to 256mb each.

I got three 128mb PC100 DIMMs, put them in, and the BIOS and the OS only see 256mb - one of the DIMMs isn't seen. Moved the DIMMs around, no difference. Always sees just 256mb instead of 384mb. Put the old 128mb DIMM back in, still sees only 256mb. I have a PDF of the P5A manual and there are no jumpers to configure with respect to memory.

I downloaded a utility called ctSPD which identifies SDRAM modules. It always detects all three DIMMs, and can tell me the make and model of each one.

Any ideas why the ctSPD utility can see there are three DIMMs but the BIOS and OS do not?
 
Looking at the manual there are a couple of possiblities. It does support up to 768MB of ram(3x256mb sticks). It says that dimms with more than 18 chips are not supported, so that could be related to your problem.
 
Thanks for the reply. I had a chance to examine the DIMMs today and none of them have more than 18 chips. I moved the DIMMs around again today and am getting the same results - ctSPD always detects the DIMM in the third slot, but BIOS and OS never do.
 
Are they double or single sided sticks that are problematic?
Might have to do with the number of banks on each stick. The manual might go into detail on this. Something like 32x8M or 8x64M or something like that - I think those sorts of numbers indicate the bank capacities.
Where's Peter when you need him...I think he does work with programming BIOSes, and he's pretty knowledgeable about this kind of stuff.
 
Dang...I just happen to have a P5A mobo sitting is a system right next to me. I do not have that many DIMMs to recreate your scenerio though. No one seems to want a little P5A system anymore.🙁
 
You must log in or register to reply here.

TRENDING THREADS

Back
Top